One known apparatus for pressing sand molds includes a squeeze board that is made of a rigid plate for pressing molding sand fed into a molding flask. However, that apparatus has a problem in that when required the pressure of the squeeze board cannot be readily varied to correspond to the shape of a pattern. Specifically, since the squeeze board is a rigid plate, although the molding sand located above the upper part of the pattern can be completely pressed, the molding sand located above the lower part of the pattern cannot he completely pressed. As a result, no uniform pressure over all the molding sand can be attained. To overcome this problem, Japanese Utility Model Publication (Kokoku) No. Hei 3-24266 discloses an apparatus for pressing sand molds wherein the squeeze board is elastic.
Also, Japanese Patent Laid-Open (Kokai) No. Hei 1-5642 discloses an apparatus for pressing sand molds wherein a plurality of squeeze heads, each operated by a hydraulic cylinder, are juxtaposed above the molding sand and directed downward such that the pressure of each squeeze head can be varied to correspond to the shape of the pattern. However, this apparatus has a problem in that since a plurality of actuators are necessary to operate each squeeze head, its cost is very high and its structure complex. This apparatus has another problem in that the squeeze head cannot press all of the molding sand near the molding flask.